Concrete joint.



UNITED STATEs PATENT OFFICE.

ERNEST LESLIE RANSOME, OF NEW YORK, N. Y.

CONCRETE JOINT.

SFEGIFIOATION forming part of Letters Patent No. 694,578, dated March l,1902. Application filed July 1'7, 1901. Serial No. 68,701. (Nospecimens.)

T0 aZZ whom it may concern:

Be it known that I, ERNEST LESLIE RAN- SOME, a citizen of the UnitedStates, residing in New York, in the State of New York, have invented anImprovementin Concrete Joints; and I hereby declare the following to bea full, clear, and exact description of the same.

My invention relates, primarily, to the joint between the lower andupper layers or courses of concrete floors and pavements; but it isapplicable to other connections; and the object thereof is to unitethese two layers more thoroughly than under certain conditions is doneat the present time.

It has been long known to the trade that a Portland-cement plaster willnot readily nor strongly unite with a Portland-cement concrete surfaceif the latter has been allowed to set hard and is rich in cement. Inlaying sidewalks, therefore, the practice is to put on the upperfinishing-layer before the lower layer sets. This is quite practicable;but in laying floors of reinforced concrete in buildings it is often notpracticable to put on the finishing or upper layer until after the firstlayer has hardened, in which case defective results frequently occurthrough the imperfect bonding together of the two layers. By my presentinvention I bond such layers together as follows: Upon the first layer,when otherwise finished but while yet unset and soft, I liberablysprinkle over the surface small pieces of honeycomb slag. By preferonceI cover the entire surface with the pieces and partly embed them intothe surface by rolling, tamping, or other means. The floor is thenallowed to rest undisturbed until it has hardened. Then wheneverconvenient all excess of the slag is swept off and the top layer is puton in the usual way.

about one-half an inch average dimension,

increasing the size to an inch and larger for heavier floors.

By preference the slag is used wet or moist.

Under the term concrete I include p1aster and all substances that act ina similar manner to concrete.

Having thus fully described my invention, what I claim, and desire tosecure by Letters Patent, is-

1. The method of bonding one body of con crete after it has set toanother body of unset concrete by the use of a course of honeycomb slagembedded into both, substantially as described.

2. The method of forming a bond between two bodies of concrete whichconsists in first sprinkling over the surface of the first-made body ofconcrete while yet soft and unset, a layer of prepared honeycombslag-,embedding the same into the surface, allowing the concrete to set,and after removing all superfluous slag, covering it and embedding itsexposed surfaces with the second body of concrete, substantially asdescribed.

ERNEST LESLIE RANSOME.

Witnesses: 1

JOHN ELLENDT, GEORGE T. ALLEN.

